Typical of factory automation is a system which comprises the combination of conveyor system and robot system. With such a system, a multiplicity of workplaces are provided along the conveyor line, and each workplace is provided with a robot for performing the work for the process assigned to the workplace. The parts or articles to be processed are transported by the conveyor at a specified speed to be worked on as specified by robots at various workplaces and progressively made into finished products. Such an automated system is suitable for a product to be made by a plurality of processes for which approximately equal periods of time can be set to execute the contemplated work, or to a product for which processes can be set with assignment of approximately equal periods of working time. When worker are used instead of robots, each process may be such that, on the average, different persons can perform the contemplated work with approximately equal periods of time.
However, there are various kinds of products which are difficult to make by such typical factory automation, for example, a product which is manufactured by a series of processes including processes wherein the work efficiency is dependent largely on the ability of the worker, and a product which involves difficulty in assigning approximately equal working periods to the processes therefor. Stitched products are examples of such products
In the case of any product, however, the improvement of productivity, which is one of the important goals, requires proper recognition and analysis of the flow of material through the production process. Further, "since the overall efficiency depends on the capability and proficiency of the workers it is also important"; to recognize and analyze the productivity of the individual workers. "Where such typical factory automation is difficult to apply"; difficulties are also encountered in obtaining at one location the data relating to the amount of work done as classified by workplaces (work areas) or processes, because the time required for work or work efficiency differs from process, to process, and the material to be worked on therefore does not flow at a constant speed from process to process. In some cases, workers may change for personal reason or to assure a balance between processes, in the amount of work done, or some workers may be located at other work sites. Thus, it is also difficult to obtain data as to the amount of work done by each worker.